Independently Rotating Wheels Research Articles

A study on Effects of Axle Misalignment of a Vehicle with Independently Rotating Wheels

This paper is concerned with the effects of the axle misalignment of a truck with independently rotating wheels (IRWs) on the wheel lateral force and flange wear. Since a truck with IRWs lacks self-steering ability, it is of concern that the wheel flange remains in contact with the rail owing to the effect of axle misalignment in parallelity, resulting in rapid wear of the flange upon continuous contact with the rail. Numerical simulations are carried out using an analytical vehicle model with axle misalignment. The obtained results are as follows. Even if misalignment is small, a vehicle with IRWs tends to run under the flange contact condition, and thus a continuous lateral force acts between the flange and rail. A vehicle with IRWs that has axle misalignment only in the lateral direction does not tend to run with continuous flange contact. In the range of misalignment in parallelity considered in this paper, the wheel lateral force increases with increasing misalignment, and the wheel lateral force acting on the IRWs increases more rapidly than that acting on the solid wheelset. The wheel lateral force generated by misalignment is equivalent to that generated during the negotiation of a curved track with a certain radius, which causes the attack angle to correspond to the angle of misalignment.

A Study on Effects of Axle Misalignment of a Vehicle with Independently Rotating Wheels

This paper deals with the effects of axle misalignment of a truck with independently rotating wheels (IRWs) on the wheel lateral force and the flange wear. Since the truck with IRWs lacks for self-steering ability, it is concerned that the wheel continues flange contact with rail due to the effects of axle misalignment in parallelity and the flange wears rapidly under the continuous flange contact condition. Numerical simulations are carried out, using an analytical vehicle model with the axle misalignment. Obtained results are as follows : Even if misalignment is a little, the vehicle with IRWs which dose not have self steering ability tends to run under the flange contact condition, and then continuous lateral force acts between the flange and the rail. The vehicle with IRWs, which has axle misalignment only in the lateral setting, does not have tendency of continuous flange contact. In the range of misalignment in parallelity considered in this paper, the wheel lateral force increases with the increase of the misalignment, and the wheel lateral force of IRW increases more than that of the solid wheelset. The wheel lateral forces generated due to the misalignment are equivalent to the ones generated in the curved tracks, the radii of which make the attack angles corresponding to the misalignment.

1103 操舵リンク系ジオメトリの非線形性を考慮した鉄道用自己操舵性独立回転車輪台車(OS2-1 交通・物流システムのダイナミクス(鉄道・エレベータ・荷役機械),OS2 交通・物流システムのダイナミクス,オーガナイズド・セッション)

Most of the bogies used for LRT have independently rotating wheels (IRW) so that the floor of the passenger compartment can be lower. IRW, however, do not have a sufficient ability to self-steer, and generate large lateral forces in curved sections of track. The EEF (a German acronym for Single-wheel Single-running-gear) bogie, on the other hand, has IRW that have the self-steering ability. The nonlinear profile of the wheels creates the gravity stiffness that gives them their self-steering ability. In this paper, a multibody dynamics model of the vehicle is developed, and a numerical simulation is conducted. Experiments with a 1/10 scale model vehicle has also been developed. From these results, a design method for the self-steering mechanism of a railway bogie, considering the nonlinear effects of linkage arrangement, is proposed.

2305 独立回転車輪車両の輪軸ミスアラインメントに起因するフランジ摩耗低減の可能性(OS4-1 接触問題とトライボロジ(その2),OS4 接触問題とトライボロジ,オーガナイズド・セッション)

Since the truck with independently rotating wheels (IRWs) lacks for self-steering ability, it is concerned that the wheel flange contacts with the rail continuously due to the effects of axle misalignment and the flange wears rapidly under the continuous flange contact. In this study, in order to decrease the flange wear due to axle misalignment of the vehicle, a potential of the modified axle supporting mechanism is examined. Here the axle supporting mechanism is composed of a longitudinal spring with lowered stiffness and a damper installed in parallel with the longitudinal spring. As a result of numerical simulation, it is found that the proposed axle supporting mechanism can decrease the flange wear caused by the axle misalignment from the point of view of a wear index.

Investigation of dynamic models of independently rotating wheels of wagons

Abstract The article deals with the modelling of independently rotating wheels (IRW) systems for wagons. The research work of the intensity of rolling stock wheels rims and flanges is observed. The main performance objectives of IRW are to reduce winding of wheel‐sets, to enable railway rolling stocks to achieve higher speeds, to decrease wear of rail and wheel rolling surface, to improve the performance on railway curves and to reduce lateral displacement on rails. IRW with profiled tread are examined and the mathematical model of these IRW is created. Finally, the peculiarities of the stability and wearing characteristics of such IRW systems are presented.

INVESTIGATION OF DYNAMIC MODELS OF INDEPENDENTLY ROTATING WHEELS OF WAGONS

The article deals with the modelling of independently rotating wheels (IRW) systems for wagons. The research work of the intensity of rolling stock wheels rims and flanges is observed. The main performance objectives of IRW are to reduce winding of wheel‐sets, to enable railway rolling stocks to achieve higher speeds, to decrease wear of rail and wheel rolling surface, to improve the performance on railway curves and to reduce lateral displacement on rails. IRW with profiled tread are examined and the mathematical model of these IRW is created. Finally, the peculiarities of the stability and wearing characteristics of such IRW systems are presented.

独立車輪台車のトルク差制御による曲線通過(車両の運動と制御(1),OS2 交通・物流機械のダイナミクス(振動,制御を含む))

From the viewpoint of the barrier-free policy, it is expected that the number of LRV with lowered-floor will increase furthermore. Trucks with independently rotating wheels (IRW) are employed in the LRV with lowered-floor. However, the truck with IRWs lacks for self-guidance ability, and then it needs some additional mechanism for running along the track. One of them is active steering mechanism using traction torque difference between two driving wheels on a non-rotational axle. This paper deals with a simulation study that examines a potential of the curving performance of a truck with IRWs by means of torque difference control of direct drive motors. The proposed steering control method, that is the same directional control of front and rear axles in a truck, has a potential to reduce the wheel lateral force of IRW over the wide range of curve radius, especially in sharp curves. Here, the control tends to steer the whole truck.

Combined active steering and traction for mechatronic bogie vehicles with independently rotating wheels

The benefits of substituting the conventional solid wheelset by independently rotating wheels (IRW) in actively steered trailed railway vehicles have already been presented in many works. If a traction system is included in this kind of vehicle it will interact strongly with the active steering system. This paper investigates how traction and active steering systems can be combined in an IRW bogie to produce a good curving performance. The combined steering and traction control concepts developed are implemented in simulation models and validated against a conventional passive vehicle.

Combined Active Steering and Traction for Mechatronic Bogie Vehicles with Independently Rotating Wheels

The benefits of substituting the conventional solid wheelset by independently rotating wheels (IRW) in actively steered trailed railway vehicles have already been presented in many works. If a traction system is included in this kind of vehicle it will interact strongly with the active steering system. This paper investigates how traction and active steering systems can be combined in an IRW bogie to produce a good curving performance. The combined steering and traction control concepts developed are implemented in simulation models and validated against a conventional passive vehicle.

Design of Active Steering Systems for Bogie-Based Railway Vehicles with Independently Rotating Wheels

SUMMARYThis paper studies the benefits of implementing active steering systems in railway vehicles mounting bogies with independently rotating wheels (IRW) and outlines a design methodology for such systems. Two possible control strategies based on physical intuition are presented, and suitable control methods are proposed for each of them. Then a validation of the system is carried out by co-simulation of the mechanical model and the control system of the vehicle using different software tools. Finally the results are discussed and some conclusions are presented.

1209 独立車輪車両の操舵方式による曲線通過性能の比較

This paper deals with curve negotiation of a rail vehicle with independently rotating wheels (IRW). In order to reduce the wheel lateral force, addition of two kinds of steering mechanism, forced and active ones, are examined by numerical simulation. As a result, it is shown that the active steering has a potential to improve the curving performance of a vehicle with IRW in anycurve radius. The forced steering, however, increases the wheel lateral force in tight curves of radius less equal 100 m and it can make the critical speed lower greatly.

Lateral Stability and Steady State Curving Performance of Unconventional Rail Trucks.

Conventional railway vehicle systems exhibit hunting phenomenon which increases component wear and imposes operating speed limits. There is also a conflict between dynamic stability and the ability of the vehicle to steer around curves. Alternatively, independently rotating wheels (IRW) in a wheelset eliminate hunting but the wheelset guidance set capability is lost. A compromise solution is made possible by a modified design that exploits a lack of fore-and-aft symmetry in the suspension design. A comparative study on steady state curving performance and dynamic stability of some unconventional truck designs is carried out. The effects of suspension and conicity are considered to evaluate the trade-off between dynamic stability and curving performance.

Solid Axle and Independently-Rotating Railway Wheelsets - A Control Engineering Assessment of Stability

Block diagram representations of both conventional wheelsets and wheelsets with independently-rotating wheels are developed, with the objective of giving insights from a control engineering viewpoint for studies of actively-controlled wheelsets. The analysis predicts a quasi-kinematic oscillation with independently-rotating wheels which has not been reported before. It also identifies possibilities for control approaches which might be used to stabilise a wheelset without affecting steady-state curving performance.

State estimation for active steering of railway vehicles

Abstract This paper presents state estimation techniques for active control of two types of railway wheelset: a conventional solid-axle wheelset and one with independently-rotating wheels (IRW). It presents a linearised dynamic model with simulation results for straight and curved track, and then the Kalman-Bucy filter is introduced to show how some primary feedback variables which are needed for active control may be estimated.

Different Lateral Dynamic Operating Conditions of a Railway Vehicle Fitted with Independently Rotating Wheels

SUMMARY This paper reports theoretical investigations done by GEC ALSTHOM related to the topic of railway vehicles with independently rotating wheels (IRW). As a first step, 2 classes of model are developed successively for the conventional wheelset and for the IRW fitted wheelset. The first class of model describes 3 dimensional dynamics of the wheelset and takes into account the 2 specific non-linearities of railway system : contact geometry and creep forces dependency on creepages. Permanent contact condition of the wheelset on the track is expressed by zero value of the 2 normal relatives velocities at the contact points, which leads to Lagrange equations with multipliers. Numerical solution by time integration of the differential algebraic set of equations involves a specific processing. A second class of models results from linearizing contact geometry and contact forces relationships assuming small deviations around an equilibrium point. These models are restricted to lateral dynamics. With help of...

A Comparative Study on Lateral Stability and Steady State Curving Behaviour of Unconventional Rail Truck Models

Conventional railway vehicle systems exhibit hunting phenomenon which increases component wear and imposes operating speed limits. There is also a conflict between dynamic stability and the ability of the vehicle to steer around curves. Alternatively, independently rotating wheels (IRW) in a wheelset eliminate hunting but the wheelset guidance capability is lost. A compromise solution is made possible by a modified design that exploits a lack of fore-and-aft symmetry in the suspension design. A comparative study on steady state curving performance and dynamic stability of some unconventional truck designs is carried out. The effects of suspension and conicity are considered to evaluate the trade-off between dynamic stability and curving performance.